Four lakes formed recently in southern Egypt in an area that was
previously desert. Fed by unusually high levels of rainfall and water
overflowing from the Aswan High Dam on the Nile River, the first lake
appeared in 1998. The Aswan's overflowing waters are channeled through
an arroyo into a reservoir, as expected, but as the high rains have
continued, so has the overflow. Consequently, the reservoir has grown
in size and three more lakes have formed.
Authorities in Egypt estimate that, together, the lakes now hold about
700 billion cubic feet of water--one quarter the Nile's total water
supply. Scientist don't know whether or not the lakes will remain, or
will dry up within a few years.
Nearly six years of regional drought and rapidly increasing demand for water have resulted in decreasing water levels in lakes throughout East Africa. The flooded regions of the Toshka Lakes west of Lake Nasser have decreased greatly over the years, exposing the former dune fields, and leaving a “bath-tub ring” of wetlands (dark region) surrounding the lake shorelines.
In the late 1990s, Egypt’s new manmade Toshka Lakes, fed from Lake Nasser via a canal, grew and spilled into new basins to become four major and two smaller lakes. Starting in 2002, astronauts have seen the lakes slowly decline, with the telltale ring of darker, moistened ground showing the previous higher water levels.